The present invention relates to an imaging table leveling system for use with a medical imaging device. More particularly the invention relates to an imaging table leveling system that levels an imaging table with respect to true level and automatically corrects table level during tilt and roll.
Medical imaging systems typically include an emitter, a detector, and an imaging table. In operation, the imaging table, on which patients are positioned, is positioned between the emitter and the detector. The emitter typically emits radiation, such as X-rays, toward the detector. The radiation typically passes through the patient positioned on the imaging table and encounters the detector. As the radiation passes through the patient, anatomical structures inside the patient cause spatial variances in the radiation received at the detector. The detector then translates the radiation variances into an image which may be employed for clinical evaluations.
As mentioned above, while imaging, the patient is positioned on an imaging table. The imaging table supports the patient but is mostly transparent to the imaging radiation so as to not interfere with the imaging of the patient. Proper positioning of the patient on the imaging table is important for a variety of reasons. For example, some imaging devices operate in confined areas. Further, positioning a patient within the imaging chamber of an imaging device may be awkward and difficult. In addition, medical procedures may be intricate and complex. Stopping a procedure to reposition a patient for imaging may be a time consuming and dangerous event. Medical imaging systems, such as X-ray imaging systems, often require extensive imaging of various portions of a patient""s body.
In order to assist in the proper positioning of the patient, some imaging tables may be re-positioned during imaging. The process of re-positioning the imaging table, or floating, typically makes the imaging process quicker and easier.
Typically, the imaging table must be level before it is floated for two reasons: First, medical images are typically more accurate when the imaging table is level. Images of the patient may be distorted if the imaging device images a patient positioned on an imaging table that is not level. Distorted images may cause an undesired misdiagnosis of the patient""s condition. Second, floating a table that is at an angle is typically more difficult to float. Therefore, leveling an imaging table is typically highly desirable.
Most imaging systems level their respective emitters and detectors to true level. While the emitters and detectors are level to true level, most imaging tables are typically level to the floor on which they are positioned. Therefore, imaging tables are typically mis-aligned with respect to true level.
Currently available systems may employ limit switches to assist in leveling an imaging table. A limit switch is a physical impediment to the angular deviation of the imaging table beyond a pre-defined range. Further, a limit switch is typically fixed to the base of the imaging table. Limit switches, however, may be undesirable because limits switches may yield a large margin of error. Additionally, limit switches are undesirable because limit switches may only level an imaging table with respect to the floor which may not itself be level.
Some imaging tables use tachometer systems to assist in the leveling process of an imaging table. A tachometer system employs tachometers to measure the speed of linear actuators that move the imaging table. The tachometers may determine how fast the actuators, which assist in imaging table positioning, are turning. Alternatively, a tachometer system may determine the angular rotation of a tachometer from a pre-calibrated level position. Tachometer systems, however, may be undesirable because tachometer systems may also yield a large margin of error. Additionally, tachometer systems typically require additional components. Also, tachometer systems may be expensive. Further, tachometer systems, as with limit switches, may only level an imaging table with respect to the floor.
Additionally, typically, limit switches and tachometers are employed to assist leveling an imaging table before the imaging table is floated. However, some imaging tables are re-positioned during imaging. Currently available systems may not be able to level such imaging tables with respect to true level during imaging.
Thus, a need has long existed for an imaging table leveling system that provides more accurate leveling. A need has also existed for an imaging table leveling system that levels an imaging table before and during floating. Also, a need has existed for an imaging table leveling system that levels the imaging table with respect to true level. Additionally, a need has existed for a more cost effective imaging table.
The present invention includes an imaging table leveling system and method for an imaging table leveling system for use with an imaging table of a medical imaging device. The imaging table leveling system levels an imaging table with respect to true level. The imaging table leveling system levels an imaging table before, or while, the imaging table is floated. The system includes an imaging table, an inclinometer, a processor, and actuators. The inclinometer continuously measures table angle data. When activated, the processor receives the table angle data from the inclinometer. The processor then compares the table angle data to a stored level constant. The processor then commands the actuators to move the imaging table until the table angle data matches the stored level constant. The table angle data is also used to correct differences in actuator rates during tilt, or longitudinal movement, and roll, or lateral movement.